The field of photomechanical processes requires photographic light-sensitive materials that give satisfactory image reproduction of originals and use stable processing solutions that are easily replenished in order to cope with the diverse and complex materials that must be printed. The diverse originals in line work, for example, are photo-composed letters, handwritten letters, illustrations, and dot prints, all of which contain images of different densities and line widths.
There has been great demand for a process camera, a photographic light-sensitive material or an image formation system that will provide excellent reproduction of the original. In the photomechanical processing of catalogues or large posters, on the other hand, enlargement or reduction of a dot print is primarily used. When a dot print is enlarged in plate making, the line number per inch is reduced and the dots blurred. When a dot print is reduced, the line number per inch increases and the dots become finer than the original. Accordingly, an image formation system having a broader latitude than presently known that would maintain the reproducibility of halftone gradation is also desired.
A halogen lamp or a xenon lamp is commonly used as the light source for a process camera. In order to obtain photographic sensitivity to these light sources, photographic materials are usually subjected to orthochromatic sensitization. However, orthochromatic photographic materials are more susceptible to the effects of lens chromatic aberration and thus the image quality is more likely to deteriorate. This deterioration is most conspicuous when using a xenon lamp.
Known systems meet the demand for broad latitude. For example, one such method involves processing a lith type silver halide light-sensitive material containing silver chlorobromide (containing at least 50% silver chloride) with hydroquinone developing solution having an extremely low effective sulfite ion concentration (usually 0.1 mol/l or less) to obtain a line or dot image having high contrast and high density in which image areas and non-image areas are clearly distinguished. However, the developer used with this method is extremely sensitive to air oxidation due to the low sulfite concentration. This necessitates various efforts and devices to stabilize the developer which result in a reduction of the processing speed and a reduction in working efficiency.
Such problems have created a demand for an image formation system which eliminates the image formation instability associated with the above-described lith development system and provides an ultrahigh contrast image by using a processing solution having satisfactory preservation stability. One solution that was proposed is to process a surface latent image type silver halide photographic material containing a specific acylhydrazine compound with a developing solution having a pH between 11.0 and 12.3 and containing at least 0.15 mol/l of a sulfite preservative. Such a process has developer with satisfactory stability and forms an ultrahigh contrast negative image having a gamma exceeding 10 (see, U.S. Pat. Nos. 4,166,742, 4,168,977, 4,221,857, 4,224,401, 4,243,739, 4,272,606, and 4,311,781). Such an image formation system can also use silver iodobromide and silver chloroiodobromide as well as silver chlorobromide. In contrast, more conventional ultrahigh contrast image formation systems can only use photographic materials of silver chlorobromide having high silver chloride content.
The above-described image formation system exhibits excellent performance in dot quality, stability of processing, rapidness of processing, and reproducibility of originals. However, a system that provides still further improvement in reproducibility of originals is desired in order to cope with the present diversity of originals to be printed.
An attempt to broaden the area of gradation that could be reproduced was made using a photographic light-sensitive material containing a redox compound capable of releasing a photographically useful group upon oxidation (see, JP-A-61-213847 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") and U.S. Pat. No. 4,684,604). However, if an ultrahigh contrast image formation system using a hydrazine derivative is combined with these redox compounds, the redox compounds disrupt the high contrast effect.